Tweaks:
Custom CSS for Firefox - https://github.com/Aris-t2/CustomCSSforFx/releases/
Firefox CSS Hacks - https://github.com/MrOtherGuy/firefox-csshacks/
Menu Icon Plus CSS - https://github.com/B00ze64/FF-Menu-Icon-Plus-CSS/releases/
Simple Def Theme - https://addons.mozilla.org/en-US/firefox/addon/simple-def/
Winaero Firefox - https://winaero.com/category/firefox/
Add-ons:
Don't track me Google - https://addons.mozilla.org/en-US/firefox/addon/dont-track-me-google1/
F.B. Purity - https://www.fbpurity.com/
Open in MS Edge - https://addons.mozilla.org/en-US/firefox/addon/open-in-microsoft-edge-browser/
Show/Hide passwords - https://addons.mozilla.org/en-US/firefox/addon/showhide-passwords/
uBlock Origin - https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/
Webmail Ad Blocker - https://addons.mozilla.org/en-US/firefox/addon/webmail-ad-blocker/
YouTube High Definition - https://addons.mozilla.org/en-US/firefox/addon/youtube-high-definition/
YT Anno. No More - https://addons.mozilla.org/en-US/firefox/addon/youtubes-annotations-no-more/
Zoom Image - https://addons.mozilla.org/en-US/firefox/addon/zoom-image/